Protest parties racked up gains across the 28-nation European Union in elections to the bloc’s Parliament, turning the assembly designed to unite Europe into an echo chamber for politicians who want to tear it apart.

The wave hit hardest in France, Greece and the U.K., undermining the leaders of those countries and making it more difficult to steer the EU as a whole. In all, fringe parties won 31 percent of the Europe-wide vote, up from 20 percent in the current Parliament, according to official EU projections.

Political forces suspicious of the U.S. made inroads across the continent, threatening to snag trans-Atlantic trade talks the EU hopes will spur an economy struggling with the after- effects of the euro debt crisis.

The protest vote “will have a huge impact on the parties and policies back home,” said Pieter Cleppe, head of the Brussels office of U.K.-based think tank Open Europe. “They will make it harder to centralize powers in the EU, especially when it comes to managing the euro crisis.”

United mainly by opposition to European unity, the anti- establishment movements show no signs of agreeing on a policy program. Instead, their aim was to make life harder for people who weren’t on the ballot: leaders of national governments.

Cameron’s Defeat

In Britain, the U.K. Independence Party beat Prime Minister David Cameron’s Conservatives into third place with a campaign to yank the country out of the EU.

In France, Marine Le Pen’s National Front parlayed complaints about too many immigrants and a lenient penal system into 26 percent of the vote. The breakthrough by the National Front, which has just three out of 577 lawmakers in the national parliament, dealt a further blow to President Francois Hollande, the least popular leader in France’s modern history.

Proclaiming “politics of the French, for the French, with the French,” Le Pen said the election was a “humiliation” for Hollande. She called on him to dissolve the French parliament and submit to new national elections -- an appeal that was dismissed by Hollande’s camp.

Voters in Greece, the epicenter of the euro crisis, handed first place to Syriza, a party which chafed at the budget cuts demanded by German-led creditors in exchange for international aid. A near-final count gave it 26.6 percent. Prime Minister Antonis Samaras’s New Democracy party, which has a two-seat majority in the national parliament, trailed with 22.7 percent.

Bonds Buoyed

Samaras’s junior coalition partner, Pasok, got 8 percent, keeping the ruling parties on top and avoiding an electoral embarrassment. Samaras is now counting on an easing of terms for the repayment of Greece’s debt. Expectations that he will stay in power buoyed Greek bonds today, pushing the 10-year yield down 27 basis points to 6.23 percent at 3:25 p.m. in Athens.

The 751-member European assembly will have a voice in naming the next president of the European Commission, the EU’s executive arm. On that point, the mainstream parties still hold sway. The latest count gave center-right parties 214 seats, leading their standard-bearer, former Luxembourg Prime Minister Jean-Claude Juncker, to claim the commission post. The Socialists, led by Germany’s Martin Schulz, got 189 seats. A deal between the two political groups may be the only avenue to a majority.

German Chancellor Angela Merkel told reporters in Berlin that EU leaders will discuss the appointment when they meet over dinner in Brussels tomorrow.

Parliamentary Role

Instead of fostering a U.S.-style popularity contest, the campaign for commission presidency failed to distract voters from domestic issues. National governments decide bread-and- butter policies like taxes, spending, health care, education and pensions. The European Parliament plays a role in setting EU- wide laws in areas such as transport, product safety, the environment and banking.

While far from dictating 75 percent of national laws as asserted by UKIP leader Nigel Farage, the EU Parliament serves as a lightning rod for economic and social grievances. The protest vote was a sum of contradictions. Austria’s Freedom Party argued that bailouts for debt-stricken southern countries were too generous; Syriza contended they weren’t generous enough.

Politicians with anti-EU bullhorns achieved something that had eluded pro-Europeans ever since the first European Parliament elections in 1979: a halt to the steady decrease in turnout. Some 43.1 percent of the 400 million eligible European voters cast ballots, up from 43 percent in 2009.

‘Warning Bell’

The stampede to the fringes is “a very serious warning bell to the democratic parties in Europe,” Sergei Stanishev, a former Bulgarian prime minister who heads the EU-wide socialist group, told reporters in Brussels today.

Britain’s victor was Farage’s UKIP, which took 27 percent of the vote, followed by the main opposition Labour Party at 25 percent and Cameron’s Conservatives with 24 percent.

Farage said his goal is to rattle Cameron’s government, forcing curbs on immigration and paving the way to a referendum on Britain quitting the EU as soon as possible.

“We’re going to get a good number of euro-skeptics elected to the European Parliament,” Farage told Brussels reporters via video link. “Whether that makes a big difference in European politics remains to be seen, but it’s going to make a big difference in domestic politics.”

German support dipped for Merkel, the dominant figure in European debt-crisis diplomacy. While her Christian Democratic Union-led bloc placed first, it did so with 35.4 percent of the vote, down from 42 percent in last year’s national election. The anti-euro Alternative for Germany party won its first seats in any election with 7 percent.

One exception to the European rule came in Italy, where Prime Minister Matteo Renzi’s Democratic Party defeated the populist challenge of Beppe Grillo’s Five Star Movement. Renzi, 39, in office since February, may use the victory in his first national vote as a mandate for further economic deregulation. Italian bonds surged, with the 10-year yield falling 12 basis points to 3.03 percent at 2:31 p.m. in Rome.